Flexible torque cable for delivery of medical devices

ABSTRACT

The present disclosure describes delivery cables for delivering a medical device. In one embodiment, a delivery cable includes a flexible inner core, a proximal outer coil, and a distal outer coil. The proximal outer coil has a first rigidity. The distal outer coil surrounds at least a portion of a distal section of the flexible inner core and has a second rigidity less than the first rigidity thereby, thereby reducing bias placed on the medical device by the delivery cable.

CROSS REFERENCE OF RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 15/903,432, filed on Feb. 23, 2018, which claims priority toU.S. Provisional Application Ser. No. 62/462,661, filed Feb. 23, 2017;62/478,883, filed Mar. 30, 2017; and 62/503,061, filed May 8, 2017 eachof which are incorporated by reference herein in their entirety.

BACKGROUND OF THE DISCLOSURE Field of Disclosure

The present disclosure generally relates to a medical device deliverycable and methods of making and using the same. In particular, thepresent disclosure relates to a medical device delivery cable includinga flexible inner member, a proximal outer member to provide columnstrength and rigidity to the delivery cable, and a distal outer memberto provide flexibility to the delivery cable. Methods of manufacturingand using the medical device delivery cables are also disclosed.

Background Art

Delivery devices including, among other components, catheters anddelivery cables are used for an ever-growing number of procedures, andin particular, for the delivery of medical devices to a target site.Typically, the catheter is manipulated through the patient's vasculatureand to the intended site, for example, a site within the patient's heartor other organ and the delivery cable is used to advance the medicaldevice through the catheter and to the target site. Once the medicaldevice has reached the target site, the delivery cable may be detachedor uncoupled from the medical device such that the medical device isdeployed from both the catheter and the delivery cable.

Generally, the catheter would have an overall outside diameter smallenough to negotiate blood vessels or other anatomy while retaining aninner diameter (“bore size”) large enough to accommodate the medicaldevice (and delivery cable) therethrough. Since the path within thepatient may be long, tortuous, and/or involve intricate placement of amedical device(s), maneuverability via steering the catheter may beparticularly beneficial. Furthermore, the delivery cable must be rigidenough so as to be capable of maneuvering the medical device through thecatheter while still being flexible enough to accommodate the tortuouspath through which it must travel to the target site.

SUMMARY OF THE DISCLOSURE

The present disclosure is directed to a delivery cable that includes aflexible inner core, a proximal outer coil having a first rigidity, anda distal outer coil surrounding at least a portion of a distal sectionof the flexible inner core and having a second rigidity less than thefirst rigidity, thereby reducing bias placed on the medical device bythe delivery cable.

The present disclosure is further directed to a delivery device fordelivering a medical device to a target site, the delivery deviceincluding an outer sheath, and a delivery cable positioned within theouter sheath and movable along a longitudinal axis with respect to theouter sheath. The delivery cable includes a flexible inner core, aproximal outer coil having a first rigidity, and a distal outer coilsurrounding at least a portion of a distal section of the flexible innercore and having a second rigidity less than the first rigidity, therebyreducing bias placed on the medical device by the delivery cable.

The present disclosure is further directed to a method for implanting amedical device at a target site in a subject using a delivery cable anda delivery sheath. The method includes deploying the delivery sheathinto the subject. The method further includes advancing the deliverycable through the deployed delivery sheath, the delivery cable includinga flexible inner core, a proximal outer coil having a first rigidity,and a distal outer coil surrounding at least a portion of a distalsection of the flexible inner core and having a second rigidity lessthan the first rigidity, wherein the relative dimensions of an outerdiameter of the distal outer coil and an inner diameter of the deliverysheath reduce snaking of the delivery cable within the delivery sheath.The method further includes continuing to advance the delivery cableuntil the medical device exits the delivery sheath and reaches thetarget site, wherein the distal outer coil and flexible inner corereduce bias placed on the medical device by the delivery cable when thedistal outer coil and flexible inner core are in a bent configuration.The method further includes deploying the medical device at the targetsite by detaching the medical device from the delivery cable.

The foregoing and other aspects, features, details, utilities, andadvantages of the present disclosure will be apparent from reading thefollowing description and claims, and from reviewing the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of an introducer orcatheter assembly in which the principles described herein may beimplemented;

FIG. 2 is a schematic diagram of a portion of the assembly shown in FIG.1 in combination with one embodiment of a delivery cable and a medicaldevice;

FIG. 3 is a perspective view of the delivery cable shown in FIG. 2 ;

FIG. 4 is a longitudinal cross-sectional view of the delivery cableshown in FIG. 2 ;

FIG. 5 is a longitudinal cross-sectional view of a delivery cableaccording to another embodiment that may be used with the assembly shownin FIG. 1 ;

FIG. 6 is an axial cross-sectional view of a flexible inner memberaccording to one embodiment that may be used with the delivery cableshown in FIG. 4 or FIG. 5 ;

FIG. 7 is a flow diagram of a method of manufacturing a delivery cableaccording to one embodiment;

FIG. 8 is a flow diagram of a method for implanting a medical device ata target site according to one embodiment;

FIG. 9 is a longitudinal cross-sectional view of one embodiment of adelivery cable including a coupler that may be used with the assemblyshown in FIG. 1 ;

FIG. 10 is a longitudinal cross-sectional view of another embodiment ofa delivery cable including a coupler that may be used with the assemblyshown in FIG. 1 ;

FIG. 11 is a longitudinal cross-sectional view of another embodiment ofa delivery cable including a coupler that may be used with the assemblyshown in FIG. 1 ;

FIG. 12 is a longitudinal cross-sectional view of another embodiment ofa delivery cable including multiple couplers that may be used with theassembly shown in FIG. 1 ;

FIG. 13 is a longitudinal cross-sectional view of another embodiment ofa delivery cable including multiple couplers that may be used with theassembly shown in FIG. 1 ;

FIG. 14 is a longitudinal cross-sectional view of another embodiment ofa delivery cable including multiple couplers that may be used with theassembly shown in FIG. 1 ; and

FIG. 15 is a schematic view of a tapered wire that may be used to formanother embodiment of a distal outer member that may be used with theassembly shown in FIG. 1 .

DETAILED DESCRIPTION OF THE DISCLOSURE

Septal occluders or other collapsible medical devices may be deliveredthrough a catheter or delivery sheath and to a target site using arelatively stiff delivery cable. The stiffness of the delivery cableprovides the column strength required to push the occluder through thecatheter. However, the stiffness of the cable may also tend to pulland/or bias the occluder after deployment and prior to release of theoccluder from the delivery cable, creating unpredictability in theoccluder's final position. Further, although at least some deliverycables include a flexible distal section, the flexible distal sectionmay cause the delivery cable to “snake,” or curve, during advancementthrough the delivery sheath, which may result in an increase in theforce required to advance the septal occluder.

Accordingly, the present disclosure is directed to a delivery cablecomprising a rigid proximal portion and a flexible distal portion. Thedelivery cable is configured so as to have sufficient torque and columnstrength sufficient to deliver a medical device to a target site whilealso having sufficient flexibility to navigate through a patient'svasculature and to reduce movement of a medical device upon deploymentof the medical device from the delivery cable.

The systems and methods described herein provide a delivery cable thatincludes a stiff proximal section to provide column strength and aflexible distal section to reduce an amount of bias that the deliverycable places on a medical device being delivered (e.g., a collapsiblemedical device, such as an occluder). The delivery cable includes aflexible inner member, or core, a more rigid proximal outer member, anda flexible distal outer member surrounding a distal portion of theflexible inner member. The rigid proximal outer member is configured toprovide sufficient column strength to assist in delivering the medicaldevice through a catheter or delivery sheath and sufficient torque toassist in removing the medical device from the delivery cable viarotation of the delivery cable, even in tortuous or challenging anatomy.

In contrast, the flexible distal outer member provides increasedflexibility to the delivery cable during release of the medical devicefrom the delivery cable upon deployment of the medical device. That is,the increased flexibility of the distal portion of the delivery cablereduces the tendency of the medical device to move, “jump,” pull, orbias upon detaching the delivery cable from the medical device, whichincreases the predictability of the final position of the medical deviceafter deployment thereof.

Further, the distal outer member of the delivery cables described hereinhave an outer diameter sized so as to reduce “snaking,” curving, orbunching of the delivery cable during advancement through the catheteror other delivery sheath. In particular, by increasing the outerdiameter of the delivery cable at the distal end thereof (as compared toouter diameter of the flexible inner member alone) such that itapproximates the inner diameter of the catheter or delivery sheaththrough which it is advanced during delivery of a medical device, theability of the delivery cable to “snake,” curve, or bunch within thecatheter or delivery sheath is reduced, thus reducing the amount offorce necessary to advance the medical device through the catheter ordelivery sheath. Further, by configuring the distal outer member to havea relatively short length as compared to the delivery cable overall, theability of the delivery cable to “snake,” curve, or bunch within thecatheter or delivery sheath is further reduced.

Referring now to the Figures, FIG. 1 is a perspective view of a catheterassembly or introducer assembly 110 according to one embodimentincluding a catheter or an introducer 100 having a proximal portion 150and a distal portion 190. Introducer 100 may be operably connected to ahandle assembly 106 which assists in guiding or steering the introducerduring procedures. Introducer assembly 110 further includes a hub 108operably connected to an inner lumen (not shown) within the handleassembly 106 for insertion or delivery of catheter assemblies, fluids,or any other devices known to those of ordinary skill in the art.Optionally, introducer assembly 110 further includes a valve 112operably connected to hub 108.

FIG. 2 is a schematic diagram of a portion of introducer 100 shown inFIG. 1 in combination with one embodiment of a delivery cable 200 and amedical device 201. As shown in FIG. 2 , delivery cable 200 extends fromdistal portion 190 of introducer 100 (i.e., a delivery sheath 203 ofintroducer 100), and is coupled to medical device 201. In thisembodiment, medical device 201 is a collapsible occluder. Alternatively,medical device 201 may be any device capable of being coupled todelivery cable 200. FIG. 3 is a perspective view of the delivery cable200. As described in detail below, delivery cable 200 includes a distalouter member 208, a proximal outer member 210, an inner member 202 (notshown in FIG. 3 ), and an endscrew 212.

FIG. 4 is a longitudinal cross-sectional view of delivery cable 200.Delivery cable 200 may be used to facilitate delivering a medical devicesuch as, but not limited to, a collapsible occluder or the like. Itshould be noted that although delivery cable 200 is described herein asbeing useful in combination with introducer 100 illustrated in FIGS. 1and 2 , delivery cable 200 may be used in the delivery process of manyvarious medical devices and in combination with many various sheaths,loaders, valves, etc.

As shown in FIG. 4 , delivery cable 200 includes a flexible inner member(also referred to herein as a flexible core) 202. Delivery cable 200 hasa distal section 204 and a proximal section 206. At least a portion ofinner member 202 is surrounded by a distal outer member or coil 208 atdistal section 204, and at least a portion of inner member 202 issurrounded by a proximal outer member or coil 210 at proximal section206. An endscrew 212 is coupled to a distal end of inner member 202 tofacilitate selectively attaching and detaching a medical device todelivery cable 200. For example, endscrew 212 may include a threadedportion configured to cooperate with a corresponding threaded portionpositioned on or within the medical device to be delivered such that themedical device may be engaged or disengaged (i.e., coupled to orreleased from) delivery cable 200 upon rotation of delivery cable 200,and thus rotation of endscrew 212. Endscrew 212 is attached to innermember 202 via any method suitable to sufficiently secure endscrew 212to inner member 202. For example, suitable methods include, but are notlimited to, bonding via an adhesive (such as an epoxy), connecting(e.g., using a coupling member, such as a stainless steel tube orplatinum-iridium marker band that is dome welded to a distal end ofinner member 202 prior to being crimp or spot welded to endscrew 212),soldering, welding, spot welding or crimp welding, clamping, swaging,crimping, or any combination thereof. Endscrew 212 and inner member 202may also be integrally formed (e.g., an overmolded screw). Further, inother embodiments, as an alternative to endscrew 212, any suitabledevice for attaching and detaching a medical device may be used.

Inner member 202 is formed of any material and has any configurationsuitable to provide both torque strength and flexibility to deliverycable 200 and enables delivery cable 200 to function or operate asdescribed herein. For example, inner member 202 may be configured so asto optimize torque strength and/or flexibility by modifying a length ofinner member 202, a diameter or number of wires that may form innermember 202, a number of layers forming inner member 202, and/or thewinding direction for each such layer.

For example, in one embodiment, inner member 202 is a multi-filarnitinol or stainless steel core that has a 1×7+5 construction. In thisembodiment, as illustrated in FIG. 6 and discussed in more detail below,inner member 202 includes two outer layers formed using right-hand woundnitinol wires, and has an outer diameter of approximately 0.0303 inches(0.76962 millimeters (mm)). In other embodiments, inner member 202 mayhave an outer diameter from 0.02 inches (0.508 mm) to 0.060 inches(1.524 mm), including but not limited to about 0.02 inches (0.508 mm),about 0.03 inches (0.762 mm), about 0.04 inches (1.016 mm), about 0.05inches (1.27 mm), and about 0.06 inches (1.524 mm).

The orientation of the outer two layers of nitinol wires of inner member202 (i.e., both right-hand wound), aides in providing maximum torquestrength during release or disengagement of a medical device fromdelivery cable 200 during deployment thereof (and an increasedflexibility and torque strength as compared to as least some other knowndelivery cables). In an alternative embodiment, the outer two layers maybe oriented in opposite directions (i.e., one right-hand wound and oneleft-hand wound) so as to create a bi-directional torque. Further, insome embodiments, inner member 202 may include a tapered configurationso as to provide a transition from a more rigid proximal portion to amore flexible distal portion. In such embodiments, the outer diameter ofinner member 202 could range from 0.020 inches to 0.060 inches dependingon the desired flexibility and torque strength.

As noted above, proximal outer member 210 surrounds inner member 202 ata proximal section 206 thereof. Inner member 202 extends through anylength of proximal outer member 210 sufficient to enable the coupling orattaching of inner member 202 to proximal outer member 210. For example,as shown in FIG. 4 , inner member 202 may only extend through a portionof the length of proximal outer member 210, wherein the section ofoverlap between inner member 202 and proximal outer member 210 (i.e.,the length of delivery cable 200 along which inner member 202 extendsthrough proximal outer member 210) is sufficient to enable the couplingthereof. In other embodiments, however, inner member 202 may extendthrough an entire length of proximal outer member 210. Still in otherembodiments, inner member may include a proximal portion extendingthrough proximal section 206 and a separate distal portion extendingthrough distal section 204, as is further illustrated with respect toFIG. 11 and further described below. In this particular embodiment, theouter diameter and overall configuration of inner member 202 at proximalsection 206 may be the same or different than the outer diameter andoverall configuration of inner member 202 at distal section 204.

Proximal outer member 210 may be coupled or attached to inner member 202by any suitable means. For example, in one embodiment, proximal outermember 210 is adhesively attached to inner member 202 via an epoxyplaced along the entire overlapping surface of proximal outer member 210or on only a portion thereof. In other embodiments, proximal outermember 210 is attached or coupled to inner member 202 by soldering,welding, spot or crimp welding, clamping, swaging, crimping, with anysuitable adhesive, or any combination thereof.

Proximal outer member 210 is also coupled at a distal end thereof to aproximal end of distal outer member 208 by any suitable means. In oneembodiment, proximal outer member 210 and distal outer member 208 areadhesively attached or coupled to one another via an epoxy. In otherembodiments, proximal outer member 210 is attached or coupled to distalouter member 208 by welding, clamping, or with any suitable adhesive.Further, in some embodiments, a transition segment (not shown in FIG. 4) is positioned at an interface between distal outer member 208 andproximal outer member 210 to provide intermediate flexibilitytherebetween.

Proximal outer member 210 is sized and configured so as to providesufficient column strength to delivery cable 200 to assist in deliveringthe medical device through a catheter or delivery sheath and sufficienttorque to assist in releasing or disengaging the medical device from thedelivery cable, even in tortuous or challenging anatomy. In oneembodiment, proximal outer member 210 is a relatively stiff multi-filarcable formed of eight 0.0185 inch (0.4699 mm) stainless steel wireswound with an outer diameter of approximately 0.075 inches (1.905 mm)and an inner diameter of approximately 0.038 inches (0.9652 mm). Inother embodiments, proximal outer member 210 may have an outer diameterfrom 0.05 inches (1.27 mm) to 0.085 inches (2.159 mm), including but notlimited to about 0.05 inches (1.27 mm), about 0.06 inches (1.524 mm),about 0.07 inches (1.778 mm), about 0.08 inches (2.032 mm), and about0.085 inches (2.159 mm). Proximal outer member 210 may be formed of anynumber of wires, having any size and shape, and arranged in anyconfiguration suitable to provide the desired flexibility and strengthof proximal outer member 210.

As illustrated in FIG. 4 , distal outer member 208 surrounds innermember 202 and extends between proximal outer member 210 and endscrew212. As described above, distal outer member 208 is attached or coupledto proximal outer member 210 by any suitable means. Distal outer member208 is sized and configured so as to provide sufficient flexibility todelivery cable 200 to prevent the tendency of the medical device beingdelivered via delivery cable 200 to move, “jump,” pull, or bias upondetaching the medical device from delivery cable 200 and to preventundesired straightening of a delivery sheath during delivery of amedical device. Distal outer member 208 is further sized and configuredso as to reduce the ability or tendency of delivery cable, and inparticular a distal portion thereof, to “snake,” curve, or bunch withinthe catheter or delivery sheath. In particular, distal outer member 208has an outer diameter (e.g., 0.068 inches (1.727 mm) or 0.085 inches(2.159 mm)) that is slightly smaller than an inner diameter of acatheter or delivery sheath through which delivery cable 200 is advancedduring delivery of a medical device. For example, distal outer member208 may have an outer diameter that is greater than 50% of the innerdiameter of the catheter or delivery sheath, including greater than 60%,greater than 70%, greater than 80%, and greater than 90% of the innerdiameter of the catheter or delivery sheath, more particularly, an outerdiameter that is greater than 95% of the inner diameter of the catheteror delivery sheath, and even more particularly, an outer diameter thatis greater than 98% of the inner diameter of the delivery sheath. Thesepercentages are exemplary. For example, those of skill in the art willappreciate that, for larger sheath diameters, different percentages maybe more suitable. By keeping the space between the catheter or deliverysheath and the outer surface of distal outer member 208 minimized, theability of distal outer member 208 to “snake,” bunch, or curve within acatheter or delivery sheath during advancement of delivery cable 200therethrough is reduced, which in turn, reduces the amount of forcerequired to advance a medical device through the catheter or deliverysheath.

The ability or tendency of distal outer member 208 to “snake,” curve, orbunch within a catheter or delivery sheath is further reduced byconfiguring distal outer member 208 to have a relatively short length ascompared to the length of delivery cable 200 overall. For example, inone embodiment, distal outer member 208 has a length of approximately 1inch (25.4 mm). In other embodiments, distal outer member 208 may have alength of from 0.5 inches (12.7 mm) to 9.5 inches (241.3 mm), includingfrom 3 inches (76.2 mm) to 9.5 inches (241.3 mm), from 0.5 inches (12.7mm) to 3.0 inches (76.2 mm), including but not limited to about 0.5inches (12.7 mm), about 0.75 inches (19.05 mm), about 1.0 inches (25.4mm), about 1.25 inches (31.75 mm), about 1.5 inches (38.1 mm), about1.75 inches (44.45 mm), about 2.0 inches (50.8 mm), about 2.25 inches(57.15 mm), about 2.5 inches (63.5 mm), about 2.75 inches (69.85 mm),about 3.0 inches (76.2 mm), about 5 inches (127 mm), about 7 inches(177.8 mm), and about 9 inches (228.6 mm).

In one specific embodiment, distal outer member 208 has an outerdiameter of approximately 0.085 inches (2.159 mm). In other embodiments,distal outer member 208 may have an outer diameter from 0.05 inches(1.27 mm) to 0.085 inches (2.159 mm), including but not limited to about0.05 inches (1.27 mm), about 0.06 inches (1.524 mm), about 0.07 inches(1.778 mm), about 0.08 inches (2.032 mm), and about 0.085 inches (2.159mm).

In one embodiment, distal outer member 208 includes tightly woundstainless steel wire having a diameter of from 0.011 inches (0.2794) to0.02 inches (0.3810 mm) forming a coil having an outer diameter of from0.05 inches (1.27 mm) to 0.085 inches (2.159 mm) and a length of from0.5 inches (12.7 mm) to 1.5 inch (38.1 mm). In one specific embodiment,distal outer member 208 includes tightly wound stainless steel wirehaving a diameter of approximately 0.014 inches (0.3566 mm) forming acoil having an outer diameter of approximately 0.068 inches (1.727 mm)and a length of approximately 1.0 inch (25.4 mm). In another specificembodiment, distal outer member 208 includes tightly wound stainlesssteel wire having a diameter of approximately 0.011 inches (0.2794 mm)forming a coil having an outer diameter of approximately 0.085 inches(2.159 mm) and a length of approximately 1.0 inch (25.4 mm).Accordingly, distal outer member 208, in one embodiment, may have alarger outer diameter than proximal outer member 210. In such anembodiment, a connector may optionally be positioned between a distalend of proximal outer member 210 and a proximal end of distal outermember 208 so as to provide a smooth transition between the differingouter diameters. In other embodiments, distal outer member 208 andproximal outer member 210 may have substantially equal outer diameters.As will be understood by those of skill in the art, the pitch, diameter,and/or material of distal outer member 208 may be modified withoutdeparting from the scope of the disclosure. For example, distal outermember 208 may be nitinol in some embodiments.

FIG. 5 is a longitudinal cross-sectional view of delivery cable 200illustrating a material that may be positioned over at least a portionof proximal outer member 210 to reduce the amount of air ingress duringadvancement of the medical device through a catheter or other deliverydevice. In one embodiment, at least a portion of the outer surface ofproximal outer member 210, and in some embodiments an entire outersurface of proximal outer member 210, is coated, sealed, or surroundedby a heat shrink material suitable to reduce or prevent air ingressduring advancement of the medical device during delivery thereof. Theheat shrink material may also extend along a portion of distal outermember 208, which may increase the securement between proximal outermember 210 and distal outer member 208 and may also increase thelubriciousness of delivery cable 200 thus aiding in a smootheradvancement of delivery cable 200 through a patient's vasculature. Forexample, as shown in FIG. 5 , a heat shrink material 302 circumscribesat least a portion of both proximal outer member 210 and distal outermember 208. In other embodiments, heat shrink material 302 maycircumscribe at least a portion of proximal outer member 210, includinga proximal-most end thereof, but not circumscribe distal outer member208. In yet another embodiment, heat shrink material 302 maycircumscribe a distal end of proximal outer member 210 and a proximalend of distal outer member 208, but not circumscribe the proximal-mostend of proximal outer member 210. Heat shrink material 302 may be formedof any heat shrink material suitable to reduce or prevent air ingressduring advancement of the medical device during delivery thereof, toincrease the securement between proximal outer member 210 and distalouter member 208, and/or to increase the lubricious of delivery cable200 while not significantly increasing the outer diameter of deliverycable 200.

Delivery cable 200 may also include indicator marks or lines (not shown)on a proximal end thereof to convey the position of delivery cable 200with respect to a delivery sheath or other delivery device to a user. Insome embodiments, the indicator marks or lines are pad printed or laseretched on heat shrink material 302. In other embodiments, the indicatormarks or lines are laser etched on a portion of proximal outer member210. In still other embodiments, a colored heat shrink materialincluding the indicator marks or lines, or indicating longitudinalplacement by varying colors, may be placed on the outer surface ofproximal outer member 210 prior to heat shrink material 302 beingapplied to delivery cable 200.

FIG. 6 is an axial cross-sectional view of flexible inner member 202. Inthis specific embodiment, inner member 202 includes a core layer 402, afirst outer layer 404 surrounding core layer 402, and a second outerlayer 406 surrounding first outer layer 404. In the specific embodiment,core layer 402 includes a single wire having a diameter of approximately0.0055 inches (0.1397 mm), first outer layer 404 includes six wires eachhaving a diameter of approximately 0.0051 inches (0.12954 mm), andsecond outer layer 406 includes five wires each having a diameter ofapproximately 0.0075 inches (0.1905 mm). In other embodiments, corelayer 402 may include a single wire having a diameter from 0.0045 inches(0.1143 mm) inches to 0.010 inches (0.254 mm), including but not limitedto about 0.0045 inches (0.1143 mm), about 0.0047 inches (0.11938 mm),about 0.0049 inches (0.12446 mm), about 0.0051 inches (0.12954 mm),about 0.0053 inches (0.13462 mm), about 0.0055 inches (0.1397 mm), about0.006 inches (0.1524 mm), about 0.007 inches (0.1778 mm), about 0.008inches (0.2032 mm), about 0.009 inches (0.2286 mm), and about 0.010inches (0.254 mm). Further, first outer layer 404 may include anysuitable number of wires each having a diameter from 0.0050 inches(0.127 mm) inches to 0.010 inches (0.254 mm), including but not limitedto about 0.0050 inches (0.127 mm) inches, about 0.00525 inches (0.13335mm), about 0.0055 inches (0.1397 mm), about 0.00575 inches (0.14605 mm),about 0.0060 inches (0.1524 mm), about 0.007 inches (0.1778 mm), about0.008 inches (0.2032 mm), about 0.009 inches (0.2286 mm), and 0.010inches (0.254 mm). In addition, second outer layer 406 may include anysuitable number of wires each having a diameter from 0.0070 inches(0.1778 mm) to 0.015 inches (0.381 mm), including but not limited toabout 0.0070 inches (0.1778 mm) inches, about 0.00725 inches (0.18415mm), about 0.0075 inches (0.1905 mm), about 0.00775 inches (0.19605 mm),about 0.0080 inches (0.2032 mm), about 0.0090 inches (0.2286 mm), about0.010 inches (0.254 mm), about 0.011 inches (0.2794 mm), about 0.012inches (0.3048 mm), about 0.013 inches (0.3302 mm), about 0.014 inches(0.3556 mm), and about 0.015 inches (0.381 mm).

Alternatively, inner member 202 may include any configuration or size ofwires that enables inner member 202 to function as described herein.That is, inner member 202 may include any configuration that facilitatesachieving a balance between flexibility and torque strength as describedherein. For example, in one embodiment, core layer 402 may be absentfrom inner member 202. In other embodiments, inner member 202 mayinclude a 1×3, 1×7, 1×7+5, 1×12 or any other similar configuration.Using a wound construction with multiple layers for inner member 202facilitates improving torque strength and flexibility. Further, eachlayer of inner member 202 may be formed from any suitable material knownin the art. For example, in one specific embodiment, each wire of secondouter layer 406 may be formed from stainless steel, or any othersuitable, weldable material, while each wire of first outer layer 404and core layer 402 may be formed of nitinol. Such a configurationprovides an increased weld strength between inner member 202 andendscrew 212 and/or couplers 902 and 940, while maintaining a desiredflexibility.

FIG. 7 is a flow diagram of a method 500 for manufacturing a deliverycable, such as delivery cable 200 (shown in FIG. 4 ), according to oneembodiment. Notably, the steps in method 500 may be performed in anysuitable order, and are not limited to being performed in the ordershown in FIG. 7 . Further, similar steps of method 500 may be used forproducing additional embodiments of a delivery cable, such as thoseillustrated in FIGS. 9-14 and described in more detail below.

Method 500 includes providing 502 a flexible inner member, such asflexible core 202. Method 500 further includes inserting 504 the innermember at least partially into a proximal outer member having a firstrigidity, such as proximal outer member 210 and coupling 505 the innermember to the proximal outer member. Method 500 further includesinserting 506 the inner member into a distal outer member having asecond rigidity, such as distal outer member 208. In this embodiment theinner member extends through an entire length of the distal outer coilso that the inner member can attach to the proximal outer member and anendscrew. Method 500 further includes coupling 508 the proximal outermember to the distal outer member. This coupling facilitates providing asmooth transition between the proximal outer member and the distal outermember, and may be accomplished, for example, using welding, a heatshrink material, or a coupler, as described herein.

FIG. 8 is a flow diagram of a method 600 for implanting a medical device(e.g., collapsible occluder) at a target site in a subject using adelivery cable and a delivery sheath, such as delivery cable 200 anddelivery sheath 203 (shown in FIG. 2 ), according to one embodiment.Notably, the steps in method 600 may be performed in any suitable order,and are not limited to being performed in the order shown in FIG. 8 .Method 600 includes deploying 602 the delivery sheath into the subject.In some embodiments, the medical device is already attached to a distalend of the delivery cable in a “preloaded” configuration. Alternatively,in other embodiments, method 600 may optionally include coupling 604 themedical device to a distal end of the delivery cable. In the embodimentsdescribed herein, delivery cable has a sufficient column strength andtensile strength for delivering and recapturing the medical device. Asdescribed above, the delivery cable includes at least a flexible innercore, a proximal outer coil having a first rigidity, and a distal outercoil surrounding at least a portion of a distal section of the flexibleinner core and having a second rigidity less than the first rigidity.Method 600 further includes advancing 606 the delivery cable through thedeployed delivery sheath. As described above, the relative dimensions ofan outer diameter of the distal outer coil and an inner diameter of thedelivery sheath facilitate reducing snaking of the delivery cable withinthe delivery sheath. Method 600 further includes continuing 608 toadvance the delivery cable until the medical device exits the deliverysheath and reaches the target site. At the target site, the relativerigidity of distal section of the delivery cable with respect to theproximal outer coil facilitates reducing bias placed on the medicaldevice by the delivery cable when the distal outer coil is in a bentconfiguration, thus reducing moving, “jumping,” pulling, or biasing upondetaching the delivery cable from the medical device. Method furtherincludes deploying 610 the medical device at the target site bydetaching the medical device from the delivery cable.

FIG. 9 is a longitudinal cross-sectional view of one embodiment of adelivery cable 900 including a coupler 902 that may be used with theassembly shown in FIG. 1 . Delivery cable 900 includes inner member 202,distal outer member 208, proximal outer member 210, and endscrew 212. Inthis embodiment, as shown in FIG. 9 , coupler 902 couples distal outermember 208 to proximal outer member 210. For example, coupler 902 may beattached to distal outer member 208 and proximal outer member 210 usinga seam weld, spot weld, tack weld or crimp weld, and coupler 902 may beattached to inner member 202 using adhesive, soldering, a spot weld orcrimp weld, clamping, crimping, or any combination thereof. Further,coupler 902 may be, for example, stainless steel. Alternatively, coupler902 may be attached to distal outer member 208, proximal outer member210, and/or inner member 202 using any suitable techniques (e.g., byusing an additional coupling member such as a stainless steel tube orplatinum-iridium marker band that is dome welded to a distal end ofinner member 202 prior to being crimp or spot welded to coupler 902).Coupler 902 may be made of any material that enables delivery cable 900to function as described herein, and facilitates a robust connectionbetween distal outer member 208, proximal outer member 210, and innermember 202.

In the embodiment shown in FIG. 9 , inner member 202 extends through theentirety of coupler 902, and into a portion of proximal outer member210. In contrast, FIG. 10 is a longitudinal cross-sectional view ofanother embodiment of a delivery cable 1000. In this embodiment, innermember 202 extends through only a portion of coupler 902, and does notextend into proximal outer member 210. For example, in the embodiment ofFIG. 10 , inner member 202 may have an outer diameter (e.g., on theorder of approximately 30 to 60 thousandths of an inch (0.762 to 1.524mm)) that is too large to be received within proximal outer member 210.

Similarly, FIG. 11 is a longitudinal cross-sectional view of anotherembodiment of a delivery cable 1200 in which an inner member does notextend through the entirety of coupler 902. This particular embodimentincludes a distal inner member 1208 and a separate proximal inner member1210. Distal inner member 1208 extends into and is secured to a distalportion 1202 of coupler 902, and proximal inner member 1210 extends intoand is secured to a proximal portion 1204 of coupler 902. A proximal endof distal outer member 208 wraps around and is secured to an outercircumference of coupler 902 at distal portion 1202, and a distal end ofproximal outer member 210 wraps around proximal inner member 1210 and issecured to the proximal end surface 1206 of coupler 902. Distal innermember 1208, proximal inner member 1210, distal outer member 208, andproximal outer member 210 are attached or secured to coupler 902 in anysuitable manner including using a seam weld, adhesive, a spot weld orcrimp weld, clamping, crimping, or any combination thereof.

In some embodiments, the delivery cable may further include anintermediate portion positioned between a distal end of the proximalouter member and a proximal end of the distal outer member. Such anintermediate portion may be more flexible than a proximal-most portionof the delivery cable, but less flexible than a distal-most portion ofthe delivery cable. Such an intermediate portion may assist in reducingthe amount of force applied to a delivery sheath or other deliverydevice during delivery of a medical device, thus reducing the tendencyof the delivery sheath to straighten during delivery of a medical devicewhile still maintaining sufficient column strength to deliver themedical device through the delivery sheath.

For example, FIG. 12 is a longitudinal cross-sectional view of anembodiment of a delivery cable 1200 including proximal outer member 210,distal outer member 208, and intermediate outer member 240. Proximalouter member 210 is coupled to intermediate outer member 240 by coupler902, and intermediate outer member 240 is coupled to distal outer member208 via coupler 940 in the same manner described above and illustratedin FIG. 11 with respect to coupler 902. As shown in FIG. 12 , the innermember is formed of three separate and distinct portions, includingdistal inner member 1208, proximal inner member 1210, and intermediateinner member 1240, coupled or secured to one another via couplers 902and 940. In particular, distal inner member 1208 extends into and issecured to a distal portion 1242 of coupler 940, and proximal innermember 1210 extends into and is secured to a proximal portion 1204 ofcoupler 902. A proximal end of intermediate inner member 1240 extendsinto and is secured to a distal portion 1202 of coupler 902, and adistal end of intermediate portion 1240 extends into and is secured to aproximal portion 1250 of coupler 940.

In one embodiment, illustrated in FIG. 12 , each of coupler 902 andcoupler 940 are configured similarly to coupler 902 illustrated in FIG.11 . In such an embodiment, a proximal end of distal outer member 208wraps around and is secured to an outer circumference of coupler 940 atdistal portion 1242, and a proximal end of intermediate outer member 240wraps around and is secured to an outer circumference of coupler 902 ata distal portion 1202. A distal end of proximal outer member 210 wrapsaround proximal inner member 1210 and is secured to the proximal endsurface 1206 of coupler 902, and a distal end of intermediate outermember 240 wraps around intermediate inner member 1240 and is secured tothe proximal end surface 1260 of coupler 940.

In another embodiment illustrated in FIG. 13 , coupler 940 is configuredsuch that a distal end of intermediate outer member 240 wraps around andis secured to an outer circumference of proximal portion 1250 of coupler940. In yet another embodiment illustrated in FIG. 14 , coupler 940couples only intermediate inner member 1240 and distal inner member1208, while distal outer member 208 extends along the length of distalinner member 1208, coupler 940, and intermediate inner member 1240. Insuch an embodiment, coupler 940 may have a different inner diameter on aproximal end thereof and a distal end thereof to allow for the use of anintermediate inner member 1240 and a distal inner member 1208 ofdifferent outer diameters. Distal outer member 208 extends across theentire outer surface of coupler 940 in this embodiment.

In each of the embodiments described above, distal inner member 1208,proximal inner member 1210, and intermediate inner member 1240 as wellas distal outer member 208, proximal outer member 210, and intermediateouter member 240 may be attached or secured to coupler 902 and coupler940 in any suitable manner including using a seam weld, adhesive,soldering, a spot weld or crimp weld, clamping, crimping, swaging, orany combination thereof. Further, each of distal inner member 1208,proximal inner member 1210, and intermediate inner member 1240 as wellas distal outer member 208, proximal outer member 210, and intermediateouter member 240 may have the same or different diameters from oneanother allowing for each component to be individually sized andconfigured to allow for the specifically desired strength andflexibility thereof, and couplers 902 and 940 may be oriented andpositioned in any suitable configuration with respect to each of distalinner member 1208, proximal inner member 1210, and intermediate innermember 1240 as well as distal outer member 208, proximal outer member210, and intermediate outer member 240 so as to form delivery cable1200. In some embodiments, instead of having a substantially constantrigidity along its entire length, distal outer member 208 and/or innermember 202 at distal section 204 has a transition section 904 (shown inFIG. 9 ). In transition section 904, the rigidity of distal outer member208 and/or inner member 202 decreases (i.e., increasing flexibility) asdistal outer member 208 and/or inner member 202 extend away fromproximal outer member 210. Transition section 904 may be sized such thatdistal outer member 208 includes a flexible portion (e.g., having alength of approximately 0.5 to 1.5 inches (12.7 to 38.1 mm)) extendingbeyond transition section 904, and such that the total length oftransition section 904 and distal outer member 208 has a length ofapproximately 0.5 inches (12.7 mm) to 9.5 inches (241.3 mm), including 3inches (76.2 mm) to 9.5 inches (241.3 mm), and including 5 inches (127mm). For example, if distal outer member 208 has an overall length ofapproximately 3.0 inches (76.2 mm), transition section may have a lengthof approximately 2.0 inches to 2.5 inches (50.8 to 63.5 mm).Alternatively, transition section 904 may extend substantially theentire length of distal outer member 208. Transition section 904 (and/orthe flexible portion) may have any dimensions that enable deliverycables 900 to function as described herein.

Transition section 904 may be formed or created in several differentways. In one example, distal outer member 208 may be a multi-strandcable, wherein transition section 904 is formed by tapering a wallthickness of distal outer member 208 using a swaging or grindingprocess. In another example, distal outer member 208 may be a nitinolcable (e.g., multi-strand or single wire, single layer or double layer),wherein transition section 904 is formed via a heat treatment that isvaried along distal outer member 208. The varied heat treatment createsa gradual change in an Austenite finish temperature (Af) along distalouter member 208. In another example, transition section 904 is formedby varying a pitch of distal outer member 208. In yet another example,transition section 904 is formed by applying a variable thicknesscoating (e.g., a metallic and/or polymer coating) to distal outer member208. In other embodiments (not shown), transition section 904 is formedat a portion of proximal outer member 210 as opposed to at a portion ofdistal outer member 208 and/or inner member 202. Such a transitionsection 904 may be formed in any of the methods described above, and mayfurther include the tapering of a distal portion of a proximal innermember 1210, such as a proximal inner member illustrated in FIGS. 11-14.

In a further example, distal outer member 208 including transitionsection 904 is formed by welding two or more outer member segmentstogether end-to-end, with the more distal outer member segments beingmore flexible than the more proximal outer member segments. The outermember segments may be multi-strand or single wire, single layer ormultiple layers, round wire or flat wire, etc. Further, each outermember segment forming distal outer member 208 may have differentconstruction and/or different wire diameters than the other outer membersegments. In addition, the stiffness of each outer member segment may bevaried using the techniques described above.

FIG. 15 is a schematic view of a tapered wire 1100 that may be used toform another embodiment of a distal outer member that may be used, forexample, with the assembly shown in FIG. 1 . Tapered wire 1100 may beformed, for example, using centerless grinding or other suitabletechniques. Tapered wire 1100 extends from a proximal end 1102 to adistal end 1104. Further, tapered wire 1100 has a first diameter 1106 atproximal end 1102 and a second diameter 1108 at distal end 1104. In thisembodiment, first diameter 1106 is larger than second diameter 1108. Forexample, first diameter 1106 may be in a range from approximately 0.013inches to 0.025 inches (0.3302 to 0.635 mm), and second diameter 1108may be in a range from approximately 0.006 to 0.017 inches (0.1524 to0.4318 mm). Alternatively, first and second diameters 1106 and 1108 mayhave any dimensions that enable tapered wire 1100 to function asdescribed herein.

In one embodiment, tapered wire 1100 includes a first segment 1110, asecond segment 1112, and a third segment 1114. In this embodiment, firstsegment 1110 has a constant diameter (e.g., first diameter 1106), adiameter of second segment 1112 gradually tapers (e.g., from firstdiameter 1106 to second diameter 1108), and third segment 1114 has aconstant diameter (e.g., second diameter 1108). Alternatively, taperedwire 1100 may include any number of segments having any dimensions thatenable tapered wire 1100 to function as described herein.

To form the distal outer member, tapered wire 1100 is wound into a coil.The resulting distal outer member may have, for example, an overalllength in a range from approximately 0.5 inches to 3.0 inches (12.7 to76.2 mm), and more particularly, of approximately 1.5 inches (38.1 mm).Further, the resulting distal outer member may include a transitionsection (over which the rigidity of the transition distal outer membervaries) having a length in a range from approximately 0.2 inches to 3.0inches (5.08 to 76.2 mm), and more particularly, of approximately 0.5inches (12.7 mm). Accordingly, tapered wire 1100 may have, for example,an overall length 1130 of approximately 30.0 inches (762 mm), and thedistal outer member, including a transition section, may have an overalllength of approximately 0.5 inches (12.7 mm) to 9.5 inches (241.3 mm),including 3 inches (76.2 mm) to 9.5 inches (241.3 mm), and including 5inches (127 mm). Alternatively, tapered wire 1100 may have any overalllength 1130, and the resulting distal outer member may have any totallength and transition section length that enables tapered wire 1100 andthe distal outer member to function as described herein.

As indicated above, tapered wire 1100 (or multiple tapered wires 1100)is wound into a coil to form the distal outer member. The coil may betight wound, open wound, or transition between tight wound to open woundalong its length. Transitioning from tight wound to open wound may beaccomplished by using a consistent pitch (because the diameter oftapered wire 1100 changes along the length of tapered wire 1100).Alternatively, transitioning from tight wound to open wound may beaccomplished using gradual changes in pitch along one portion or theentire length of the coil. Further, tapered wire 1100 may be used toform any outer member or inner member of the delivery cable describedherein.

In other embodiments, instead of the distal outer member having avarying stiffness, and similar to the embodiment described above withrespect to FIG. 14 , the inner core has a varying stiffness. Forexample, in one such embodiment, the inner core is a solid taperednitinol core wire, and the distal outer member is a flexible torquemember (e.g., a flexible torque member formed from a multi-strand and/ora multi-layer coil or a flexible torque member that may be formed usinga laser cut hypotube). In this embodiment, the nitinol core providestensile strength for the delivery cable, and transitions from stiff toflexible, and the distal outer member (which may be formed of stainlesssteel or nitinol) provides at least a portion of the torque strength forthe delivery cable. Further, in this embodiment, the inner core anddistal outer member both terminate at both distal and proximal ends.

Although a number embodiments of this disclosure have been describedabove with a certain degree of particularity, those skilled in the artcould make numerous alterations to the disclosed embodiments withoutdeparting from the spirit or scope of the disclosure. All directionalreferences (e.g., upper, lower, upward, downward, left, right, leftward,rightward, top, bottom, above, below, vertical, horizontal, clockwise,and counterclockwise) are only used for identification purposes to aidthe reader's understanding of the present disclosure, and do not createlimitations, particularly as to the position, orientation, or use of thedisclosure. Joinder references (e.g., attached, coupled, connected, andthe like) are to be construed broadly and may include intermediatemembers between a connection of elements and relative movement betweenelements. As such, joinder references do not necessarily infer that twoelements are directly connected and in fixed relation to each other. Itis intended that all matter contained in the above description or shownin the accompanying drawings shall be interpreted as illustrative onlyand not limiting. Changes in detail or structure may be made withoutdeparting from the spirit of the disclosure as defined in the appendedclaims.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

What is claimed is:
 1. A delivery device for delivering a medical deviceto a target site, the delivery device comprising: an outer sheath; and adelivery cable positioned within the outer sheath and movable along alongitudinal axis with respect to the outer sheath, the delivery cablecomprising: a flexible inner core; a proximal outer coil having a firstrigidity; and a distal outer coil surrounding at least a portion of adistal section of the flexible inner core and having a second rigidityless than the first rigidity, thereby reducing bias placed on themedical device by the delivery cable, wherein the distal outer coilcomprises at least one first wound wire having a first wire diameter,and wherein the proximal outer coil comprises at least one second woundwire having a second wire diameter greater than the first wire diameter.2. The delivery device of claim 1, wherein an outer diameter of thedistal outer coil is less than an inner diameter of the outer sheath andgreater than 90% of the inner diameter of the outer sheath, and whereinthe distal outer coil and flexible inner core reduce snaking of thedelivery cable when the delivery cable is advanced through the outersheath.
 3. The delivery device of claim 1, wherein the delivery cablefurther comprises: an endscrew coupled to a distal end of the flexibleinner core and configured to engage the medical device.
 4. The deliverydevice of claim 1, wherein a length of the distal outer coil is betweenapproximately 0.5 inches (12.7 mm) and 3.0 inches (76.2 mm).
 5. Thedelivery device of claim 1, wherein the delivery cable further comprisesa heat shrink material circumscribing at least a portion of both theproximal outer coil and the distal outer coil.
 6. The delivery device ofclaim 1, wherein the delivery cable further comprises a couplerconfigured to couple the proximal outer coil to the distal outer coil.